Q1. What's your favorite formula? Foma FV-11, formulae by Windisch, Muir, or Adams, or Pyrocat-HD, metol version of Pyrocat-HD? Why?

Q2. What films you think work the best with them?

Q3. What kind of experiments did you do (in terms of tweaking the formula), and what did you think about it?

I have played with ideas of using pyrocatechin for my next formula, but because there isn't much much less info on this reductant compared to ascorbic acid, I thought to ask about it here. I already did some search of past articles but there weren't much, and the comments were scattered among a lot of PMK related discussions. I'm interested in minimum non-selective stain, and pyro has been excluded from my developers of choice mainly for this reason.

One particular question -- TMX has a plain gelatin layer to slow down its initial development but does it stain well in pyrocatechin formulae?

Thanks!

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 08, 2002

Answers

Pyrocatechin doesn't stain if the developer contains a normal amount of Sodium sulfite. I have only tried Mimosa No. 3, a modified version with 10% Sodium hydroxide as Part B instead of Carbonate. It works good with the films I have tried it with. Efke and Tri-X, plus I got normal contrast with Maco Ort 25 and lith film by diluting the developer more. If you can't find so much information about Catechol developers, do some experiments yourself. Very exciting. :-)

-- Patric (jenspatricdahlen@hotmail.com), May 09, 2002.

Patric: I'm trying to collect pyrocatechin formulas. Could you send me the formula for Mimosa No. 3?

-- Ed Buffaloe (edb@unblinkingeye.com), May 09, 2002.

Ed, here's Mimosa No. 3 from my note:

Mimosa No. 3

Part 1:
sodium sulfite 30g
pyrocatechin 20g
potassium bromide 0.5g

Part 2:
sodium carbonate (anhydrous) 120g

Dilute 1+1+10 for use. Foma FV-11:
metol 3g
sodium sulfite 45g
sodium carbonate 30g
pyrocatechin 6g

Dilute 1+1 to 1+5 for use.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 09, 2002.

Mr. Suzuki was faster than me. I guess that's because Suzuki is a motorcycle, and I have only an ordinary bike. ;-) The formula is correct. I got nasty streaks and bubbles with Mimosa No. 3 with some films, because of carbon dioxide gas developing from the part B. 10 ml 10% Sodium hydroxide solution per liter working solution works better.

-- Patric (jenspatricdahlen@hotmail.com), May 09, 2002.

Here's another old recipe, from the 30's I believe:

Fine grain developer by Herrman

Metol 9 g

Pyrocatechin 9 g

Sodium Sulphite 60 g

Sodium Carbonate 60 g

Dilute 1+9 or 1+19 before use.

-- Patric (jenspatricdahlen@hotmail.com), May 09, 2002.

By the way, I drive Nissan :-)

I think the streaking problem is related to halides released from film. When AgX is reduled, Ag(0) and HX form, but HX can further dissociate to get outside of the reaction, especially if the pH is high. If carbonate is not preferred because of gas formation, one can try Na2HPO4 buffer. (mix about equal molar quantity of NaOH to target at about pH 12.)

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 09, 2002.

Tsukini kawatte oshioki yo!

Thanks for the suggestion. Isn't Sodium Phosphate used for neutralizing acids? I don't know as much about chemistry as you do, but if I remember it correctly, Sodium Phosphate is mildly basic.

-- Patric (jenspatricdahlen@hotmail.com), May 09, 2002.

Phosphoric acid has three arms where protons can attach. There may be one, two or three protons on each molecule, where the likelihood depends on pH. (The higher the pH, more OH- are available and they try to take away the H+ from the phosphate. It's the same as how hydroquinone, ascorbic acid etc are activated at higher pH, though they are losing H from their -OH to make O-. When these dissociation accompanies different optical properties, they are used as pH indicator dyes.) When you say sodium phosphate you should figure out which version you are talking about. Na2HPO4 is often said "dibasic form." Whichever form you get, as long as it's something-PO4, you can adjust to a desired pH by adding NaOH solution while monitoring the pH. Dibasic one requires least NaOH if you are looking at pH near or above 12.

I wish there was a book combining chemistry, physics and practical accumulation of empirical data like Troop's book.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 09, 2002.

Ed Buffaloe would love this kind of stuff (probably? :-)

I forgot to say Foma FV-11 formulae call for anhydrous carbonate (30g) and sulfite (45g) and water to make 1 liter. Foma's recommendation is about 3min at 1+1, 8min at 1+3, 15min at 1+5.
Here's a Pextral two-bath solution.

Bath 1:
pyrocatechin 1.5g
sodium sulfite anhydrous 0.3g
water to make 300ml
process for 2 min at 20C

Bath 2:
sodium hydroxide 6g
water to make 300ml
process for 1 min at 20C

Metol can replace pyrocatechin. But what's the point? The formula looks pretty harsh and old, needs some radical modification but this is the only two bath formula using pyrocatechin that I know of! (BTW, does anyone care to comment on DiXactol??

I found these at Leszek Major's homepage.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 09, 2002.

From the "Encyclopedia of Photography" pg.446-

Sodium tribasic phosphate is recommended by Messrs. Lumiere as an accelerator:-

A. Pyrocatechin 22g. Sodium sulfite 110g. water 1000ccs B. Tri-Sodium phosphate 14g. water 1000 ccs Add 1 part of each of A and B to 1 part water.

I've already E-mailed Ed a formula about a Pyrocatechin paper developer and noted to him that Thornton's DiXactol is a Pyrocatecin/glycin based developer. Haven't tried it, Yet.

-- Garry D. Lewis (glewis@ftw.nrcs.usda.gov), May 10, 2002.

Actually, trisodium phosphate works. 2% solution gives pH of about 12. 7%, 12.4. 14%, 12.6. It's just impossible to adjust pH and buffering power independently over a wide range with a single agent like this. Apparently, Messrs is not interested in compensating effect so it makes little difference to him (except one is easier to mix than two).

One thing about pyrocatechin is that it has good chelating effect, and if the water is mineral rich this may deprive some of the developing agent. Trisodium phosphate also has chelating effect so it should help... especially if single stock solution is prepared just before use with some trisodium phosphate dissolved first into water. How much difference it makes? I don't know. I never had trouble with my tap water.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), May 10, 2002.